[mirror_ubuntu-bionic-kernel.git] / fs / quota / quota.c

/*
 * Quota code necessary even when VFS quota support is not compiled
 * into the kernel.  The interesting stuff is over in dquot.c, here
 * we have symbols for initial quotactl(2) handling, the sysctl(2)
 * variables, etc - things needed even when quota support disabled.
 */

#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/slab.h>
#include <asm/current.h>
#include <linux/uaccess.h>
#include <linux/kernel.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/capability.h>
#include <linux/quotaops.h>
#include <linux/types.h>
#include <linux/writeback.h>

static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
				     qid_t id)
{
	switch (cmd) {
	/* these commands do not require any special privilegues */
	case Q_GETFMT:
	case Q_SYNC:
	case Q_GETINFO:
	case Q_XGETQSTAT:
	case Q_XGETQSTATV:
	case Q_XQUOTASYNC:
		break;
	/* allow to query information for dquots we "own" */
	case Q_GETQUOTA:
	case Q_XGETQUOTA:
		if ((type == USRQUOTA && uid_eq(current_euid(), make_kuid(current_user_ns(), id))) ||
		    (type == GRPQUOTA && in_egroup_p(make_kgid(current_user_ns(), id))))
			break;
		/*FALLTHROUGH*/
	default:
		if (!capable(CAP_SYS_ADMIN))
			return -EPERM;
	}

	return security_quotactl(cmd, type, id, sb);
}

static void quota_sync_one(struct super_block *sb, void *arg)
{
	int type = *(int *)arg;

	if (sb->s_qcop && sb->s_qcop->quota_sync &&
	    (sb->s_quota_types & (1 << type)))
		sb->s_qcop->quota_sync(sb, type);
}

static int quota_sync_all(int type)
{
	int ret;

	if (type >= MAXQUOTAS)
		return -EINVAL;
	ret = security_quotactl(Q_SYNC, type, 0, NULL);
	if (!ret)
		iterate_supers(quota_sync_one, &type);
	return ret;
}

static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id,
		         struct path *path)
{
	if (!sb->s_qcop->quota_on && !sb->s_qcop->quota_on_meta)
		return -ENOSYS;
	if (sb->s_qcop->quota_on_meta)
		return sb->s_qcop->quota_on_meta(sb, type, id);
	if (IS_ERR(path))
		return PTR_ERR(path);
	return sb->s_qcop->quota_on(sb, type, id, path);
}

static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
{
	__u32 fmt;

	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
	if (!sb_has_quota_active(sb, type)) {
		mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
		return -ESRCH;
	}
	fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
	if (copy_to_user(addr, &fmt, sizeof(fmt)))
		return -EFAULT;
	return 0;
}

static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
{
	struct if_dqinfo info;
	int ret;

	if (!sb->s_qcop->get_info)
		return -ENOSYS;
	ret = sb->s_qcop->get_info(sb, type, &info);
	if (!ret && copy_to_user(addr, &info, sizeof(info)))
		return -EFAULT;
	return ret;
}

static int quota_setinfo(struct super_block *sb, int type, void __user *addr)
{
	struct if_dqinfo info;

	if (copy_from_user(&info, addr, sizeof(info)))
		return -EFAULT;
	if (!sb->s_qcop->set_info)
		return -ENOSYS;
	return sb->s_qcop->set_info(sb, type, &info);
}

static void copy_to_if_dqblk(struct if_dqblk *dst, struct fs_disk_quota *src)
{
	memset(dst, 0, sizeof(*dst));
	dst->dqb_bhardlimit = src->d_blk_hardlimit;
	dst->dqb_bsoftlimit = src->d_blk_softlimit;
	dst->dqb_curspace = src->d_bcount;
	dst->dqb_ihardlimit = src->d_ino_hardlimit;
	dst->dqb_isoftlimit = src->d_ino_softlimit;
	dst->dqb_curinodes = src->d_icount;
	dst->dqb_btime = src->d_btimer;
	dst->dqb_itime = src->d_itimer;
	dst->dqb_valid = QIF_ALL;
}

static int quota_getquota(struct super_block *sb, int type, qid_t id,
			  void __user *addr)
{
	struct kqid qid;
	struct fs_disk_quota fdq;
	struct if_dqblk idq;
	int ret;

	if (!sb->s_qcop->get_dqblk)
		return -ENOSYS;
	qid = make_kqid(current_user_ns(), type, id);
	if (!qid_valid(qid))
		return -EINVAL;
	ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
	if (ret)
		return ret;
	copy_to_if_dqblk(&idq, &fdq);
	if (copy_to_user(addr, &idq, sizeof(idq)))
		return -EFAULT;
	return 0;
}

static void copy_from_if_dqblk(struct fs_disk_quota *dst, struct if_dqblk *src)
{
	dst->d_blk_hardlimit = src->dqb_bhardlimit;
	dst->d_blk_softlimit  = src->dqb_bsoftlimit;
	dst->d_bcount = src->dqb_curspace;
	dst->d_ino_hardlimit = src->dqb_ihardlimit;
	dst->d_ino_softlimit = src->dqb_isoftlimit;
	dst->d_icount = src->dqb_curinodes;
	dst->d_btimer = src->dqb_btime;
	dst->d_itimer = src->dqb_itime;

	dst->d_fieldmask = 0;
	if (src->dqb_valid & QIF_BLIMITS)
		dst->d_fieldmask |= FS_DQ_BSOFT | FS_DQ_BHARD;
	if (src->dqb_valid & QIF_SPACE)
		dst->d_fieldmask |= FS_DQ_BCOUNT;
	if (src->dqb_valid & QIF_ILIMITS)
		dst->d_fieldmask |= FS_DQ_ISOFT | FS_DQ_IHARD;
	if (src->dqb_valid & QIF_INODES)
		dst->d_fieldmask |= FS_DQ_ICOUNT;
	if (src->dqb_valid & QIF_BTIME)
		dst->d_fieldmask |= FS_DQ_BTIMER;
	if (src->dqb_valid & QIF_ITIME)
		dst->d_fieldmask |= FS_DQ_ITIMER;
}

static int quota_setquota(struct super_block *sb, int type, qid_t id,
			  void __user *addr)
{
	struct fs_disk_quota fdq;
	struct if_dqblk idq;
	struct kqid qid;

	if (copy_from_user(&idq, addr, sizeof(idq)))
		return -EFAULT;
	if (!sb->s_qcop->set_dqblk)
		return -ENOSYS;
	qid = make_kqid(current_user_ns(), type, id);
	if (!qid_valid(qid))
		return -EINVAL;
	copy_from_if_dqblk(&fdq, &idq);
	return sb->s_qcop->set_dqblk(sb, qid, &fdq);
}

static int quota_setxstate(struct super_block *sb, int cmd, void __user *addr)
{
	__u32 flags;

	if (copy_from_user(&flags, addr, sizeof(flags)))
		return -EFAULT;
	if (!sb->s_qcop->set_xstate)
		return -ENOSYS;
	return sb->s_qcop->set_xstate(sb, flags, cmd);
}

static int quota_getxstate(struct super_block *sb, void __user *addr)
{
	struct fs_quota_stat fqs;
	int ret;

	if (!sb->s_qcop->get_xstate)
		return -ENOSYS;
	ret = sb->s_qcop->get_xstate(sb, &fqs);
	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
		return -EFAULT;
	return ret;
}

static int quota_getxstatev(struct super_block *sb, void __user *addr)
{
	struct fs_quota_statv fqs;
	int ret;

	if (!sb->s_qcop->get_xstatev)
		return -ENOSYS;

	memset(&fqs, 0, sizeof(fqs));
	if (copy_from_user(&fqs, addr, 1)) /* Just read qs_version */
		return -EFAULT;

	/* If this kernel doesn't support user specified version, fail */
	switch (fqs.qs_version) {
	case FS_QSTATV_VERSION1:
		break;
	default:
		return -EINVAL;
	}
	ret = sb->s_qcop->get_xstatev(sb, &fqs);
	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
		return -EFAULT;
	return ret;
}

static int quota_setxquota(struct super_block *sb, int type, qid_t id,
			   void __user *addr)
{
	struct fs_disk_quota fdq;
	struct kqid qid;

	if (copy_from_user(&fdq, addr, sizeof(fdq)))
		return -EFAULT;
	if (!sb->s_qcop->set_dqblk)
		return -ENOSYS;
	qid = make_kqid(current_user_ns(), type, id);
	if (!qid_valid(qid))
		return -EINVAL;
	return sb->s_qcop->set_dqblk(sb, qid, &fdq);
}

static int quota_getxquota(struct super_block *sb, int type, qid_t id,
			   void __user *addr)
{
	struct fs_disk_quota fdq;
	struct kqid qid;
	int ret;

	if (!sb->s_qcop->get_dqblk)
		return -ENOSYS;
	qid = make_kqid(current_user_ns(), type, id);
	if (!qid_valid(qid))
		return -EINVAL;
	ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
	if (!ret && copy_to_user(addr, &fdq, sizeof(fdq)))
		return -EFAULT;
	return ret;
}

static int quota_rmxquota(struct super_block *sb, void __user *addr)
{
	__u32 flags;

	if (copy_from_user(&flags, addr, sizeof(flags)))
		return -EFAULT;
	if (!sb->s_qcop->rm_xquota)
		return -ENOSYS;
	return sb->s_qcop->rm_xquota(sb, flags);
}

/* Copy parameters and call proper function */
static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
		       void __user *addr, struct path *path)
{
	int ret;

	if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
		return -EINVAL;
	/*
	 * Quota not supported on this fs? Check this before s_quota_types
	 * since they needn't be set if quota is not supported at all.
	 */
	if (!sb->s_qcop)
		return -ENOSYS;
	if (!(sb->s_quota_types & (1 << type)))
		return -EINVAL;

	ret = check_quotactl_permission(sb, type, cmd, id);
	if (ret < 0)
		return ret;

	switch (cmd) {
	case Q_QUOTAON:
		return quota_quotaon(sb, type, cmd, id, path);
	case Q_QUOTAOFF:
		if (!sb->s_qcop->quota_off)
			return -ENOSYS;
		return sb->s_qcop->quota_off(sb, type);
	case Q_GETFMT:
		return quota_getfmt(sb, type, addr);
	case Q_GETINFO:
		return quota_getinfo(sb, type, addr);
	case Q_SETINFO:
		return quota_setinfo(sb, type, addr);
	case Q_GETQUOTA:
		return quota_getquota(sb, type, id, addr);
	case Q_SETQUOTA:
		return quota_setquota(sb, type, id, addr);
	case Q_SYNC:
		if (!sb->s_qcop->quota_sync)
			return -ENOSYS;
		return sb->s_qcop->quota_sync(sb, type);
	case Q_XQUOTAON:
	case Q_XQUOTAOFF:
		return quota_setxstate(sb, cmd, addr);
	case Q_XQUOTARM:
		return quota_rmxquota(sb, addr);
	case Q_XGETQSTAT:
		return quota_getxstate(sb, addr);
	case Q_XGETQSTATV:
		return quota_getxstatev(sb, addr);
	case Q_XSETQLIM:
		return quota_setxquota(sb, type, id, addr);
	case Q_XGETQUOTA:
		return quota_getxquota(sb, type, id, addr);
	case Q_XQUOTASYNC:
		if (sb->s_flags & MS_RDONLY)
			return -EROFS;
		/* XFS quotas are fully coherent now, making this call a noop */
		return 0;
	default:
		return -EINVAL;
	}
}

#ifdef CONFIG_BLOCK

/* Return 1 if 'cmd' will block on frozen filesystem */
static int quotactl_cmd_write(int cmd)
{
	switch (cmd) {
	case Q_GETFMT:
	case Q_GETINFO:
	case Q_SYNC:
	case Q_XGETQSTAT:
	case Q_XGETQSTATV:
	case Q_XGETQUOTA:
	case Q_XQUOTASYNC:
		return 0;
	}
	return 1;
}

#endif /* CONFIG_BLOCK */

/*
 * look up a superblock on which quota ops will be performed
 * - use the name of a block device to find the superblock thereon
 */
static struct super_block *quotactl_block(const char __user *special, int cmd)
{
#ifdef CONFIG_BLOCK
	struct block_device *bdev;
	struct super_block *sb;
	struct filename *tmp = getname(special);

	if (IS_ERR(tmp))
		return ERR_CAST(tmp);
	bdev = lookup_bdev(tmp->name);
	putname(tmp);
	if (IS_ERR(bdev))
		return ERR_CAST(bdev);
	if (quotactl_cmd_write(cmd))
		sb = get_super_thawed(bdev);
	else
		sb = get_super(bdev);
	bdput(bdev);
	if (!sb)
		return ERR_PTR(-ENODEV);

	return sb;
#else
	return ERR_PTR(-ENODEV);
#endif
}

/*
 * This is the system call interface. This communicates with
 * the user-level programs. Currently this only supports diskquota
 * calls. Maybe we need to add the process quotas etc. in the future,
 * but we probably should use rlimits for that.
 */
SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
		qid_t, id, void __user *, addr)
{
	uint cmds, type;
	struct super_block *sb = NULL;
	struct path path, *pathp = NULL;
	int ret;

	cmds = cmd >> SUBCMDSHIFT;
	type = cmd & SUBCMDMASK;

	/*
	 * As a special case Q_SYNC can be called without a specific device.
	 * It will iterate all superblocks that have quota enabled and call
	 * the sync action on each of them.
	 */
	if (!special) {
		if (cmds == Q_SYNC)
			return quota_sync_all(type);
		return -ENODEV;
	}

	/*
	 * Path for quotaon has to be resolved before grabbing superblock
	 * because that gets s_umount sem which is also possibly needed by path
	 * resolution (think about autofs) and thus deadlocks could arise.
	 */
	if (cmds == Q_QUOTAON) {
		ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
		if (ret)
			pathp = ERR_PTR(ret);
		else
			pathp = &path;
	}

	sb = quotactl_block(special, cmds);
	if (IS_ERR(sb)) {
		ret = PTR_ERR(sb);
		goto out;
	}

	ret = do_quotactl(sb, type, cmds, id, addr, pathp);

	drop_super(sb);
out:
	if (pathp && !IS_ERR(pathp))
		path_put(pathp);
	return ret;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Quota code necessary even when VFS quota support is not compiled
	3	* into the kernel. The interesting stuff is over in dquot.c, here
	4	* we have symbols for initial quotactl(2) handling, the sysctl(2)
	5	* variables, etc - things needed even when quota support disabled.
	6	*/
	7
	8	#include <linux/fs.h>
	9	#include <linux/namei.h>
	10	#include <linux/slab.h>
	11	#include <asm/current.h>
f3da9310	12	#include <linux/uaccess.h>
1da177e4	13	#include <linux/kernel.h>
1da177e4 LT	14	#include <linux/security.h>
1da177e4 LT	15	#include <linux/syscalls.h>
16f7e0fe	16	#include <linux/capability.h>
be586bab	17	#include <linux/quotaops.h>
b716395e	18	#include <linux/types.h>
8c4e4acd	19	#include <linux/writeback.h>
1da177e4	20
c988afb5 CH	21	static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
c988afb5 CH	22	qid_t id)
1da177e4	23	{
c988afb5 CH	24	switch (cmd) {
	25	/* these commands do not require any special privilegues */
	26	case Q_GETFMT:
	27	case Q_SYNC:
	28	case Q_GETINFO:
	29	case Q_XGETQSTAT:
af30cb44	30	case Q_XGETQSTATV:
c988afb5 CH	31	case Q_XQUOTASYNC:
	32	break;
	33	/* allow to query information for dquots we "own" */
	34	case Q_GETQUOTA:
	35	case Q_XGETQUOTA:
74a8a103 EB	36	if ((type == USRQUOTA && uid_eq(current_euid(), make_kuid(current_user_ns(), id))) \|\|
74a8a103 EB	37	(type == GRPQUOTA && in_egroup_p(make_kgid(current_user_ns(), id))))
c988afb5 CH	38	break;
	39	/FALLTHROUGH/
	40	default:
1da177e4 LT	41	if (!capable(CAP_SYS_ADMIN))
	42	return -EPERM;
	43	}
	44
c988afb5	45	return security_quotactl(cmd, type, id, sb);
1da177e4 LT	46	}
1da177e4 LT	47
01a05b33 AV	48	static void quota_sync_one(struct super_block sb, void arg)
01a05b33 AV	49	{
2c5f648a JK	50	int type = (int )arg;
	51
	52	if (sb->s_qcop && sb->s_qcop->quota_sync &&
	53	(sb->s_quota_types & (1 << type)))
	54	sb->s_qcop->quota_sync(sb, type);
01a05b33 AV	55	}
01a05b33 AV	56
6ae09575	57	static int quota_sync_all(int type)
1da177e4	58	{
6ae09575 CH	59	int ret;
	60
	61	if (type >= MAXQUOTAS)
	62	return -EINVAL;
	63	ret = security_quotactl(Q_SYNC, type, 0, NULL);
01a05b33 AV	64	if (!ret)
	65	iterate_supers(quota_sync_one, &type);
	66	return ret;
1da177e4 LT	67	}
1da177e4 LT	68
c411e5f6	69	static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id,
f00c9e44	70	struct path *path)
1da177e4	71	{
f00c9e44 JK	72	if (!sb->s_qcop->quota_on && !sb->s_qcop->quota_on_meta)
	73	return -ENOSYS;
	74	if (sb->s_qcop->quota_on_meta)
	75	return sb->s_qcop->quota_on_meta(sb, type, id);
	76	if (IS_ERR(path))
	77	return PTR_ERR(path);
	78	return sb->s_qcop->quota_on(sb, type, id, path);
c411e5f6	79	}
1da177e4	80
c411e5f6 CH	81	static int quota_getfmt(struct super_block sb, int type, void __user addr)
	82	{
	83	__u32 fmt;
1da177e4	84
606cdcca	85	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
c411e5f6	86	if (!sb_has_quota_active(sb, type)) {
606cdcca	87	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
c411e5f6 CH	88	return -ESRCH;
	89	}
	90	fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
606cdcca	91	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
c411e5f6 CH	92	if (copy_to_user(addr, &fmt, sizeof(fmt)))
	93	return -EFAULT;
	94	return 0;
	95	}
1da177e4	96
c411e5f6 CH	97	static int quota_getinfo(struct super_block sb, int type, void __user addr)
	98	{
	99	struct if_dqinfo info;
	100	int ret;
1da177e4	101
f450d4fe CH	102	if (!sb->s_qcop->get_info)
f450d4fe CH	103	return -ENOSYS;
c411e5f6 CH	104	ret = sb->s_qcop->get_info(sb, type, &info);
	105	if (!ret && copy_to_user(addr, &info, sizeof(info)))
	106	return -EFAULT;
	107	return ret;
	108	}
1da177e4	109
c411e5f6 CH	110	static int quota_setinfo(struct super_block sb, int type, void __user addr)
	111	{
	112	struct if_dqinfo info;
1da177e4	113
c411e5f6 CH	114	if (copy_from_user(&info, addr, sizeof(info)))
c411e5f6 CH	115	return -EFAULT;
f450d4fe CH	116	if (!sb->s_qcop->set_info)
f450d4fe CH	117	return -ENOSYS;
c411e5f6 CH	118	return sb->s_qcop->set_info(sb, type, &info);
	119	}
	120
b9b2dd36 CH	121	static void copy_to_if_dqblk(struct if_dqblk dst, struct fs_disk_quota src)
b9b2dd36 CH	122	{
18da65e7	123	memset(dst, 0, sizeof(*dst));
b9b2dd36 CH	124	dst->dqb_bhardlimit = src->d_blk_hardlimit;
	125	dst->dqb_bsoftlimit = src->d_blk_softlimit;
	126	dst->dqb_curspace = src->d_bcount;
	127	dst->dqb_ihardlimit = src->d_ino_hardlimit;
	128	dst->dqb_isoftlimit = src->d_ino_softlimit;
	129	dst->dqb_curinodes = src->d_icount;
	130	dst->dqb_btime = src->d_btimer;
	131	dst->dqb_itime = src->d_itimer;
	132	dst->dqb_valid = QIF_ALL;
	133	}
	134
c411e5f6 CH	135	static int quota_getquota(struct super_block *sb, int type, qid_t id,
	136	void __user *addr)
	137	{
74a8a103	138	struct kqid qid;
b9b2dd36	139	struct fs_disk_quota fdq;
c411e5f6 CH	140	struct if_dqblk idq;
	141	int ret;
	142
f450d4fe CH	143	if (!sb->s_qcop->get_dqblk)
f450d4fe CH	144	return -ENOSYS;
74a8a103 EB	145	qid = make_kqid(current_user_ns(), type, id);
	146	if (!qid_valid(qid))
	147	return -EINVAL;
	148	ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
c411e5f6 CH	149	if (ret)
c411e5f6 CH	150	return ret;
b9b2dd36	151	copy_to_if_dqblk(&idq, &fdq);
c411e5f6 CH	152	if (copy_to_user(addr, &idq, sizeof(idq)))
	153	return -EFAULT;
	154	return 0;
	155	}
	156
c472b432 CH	157	static void copy_from_if_dqblk(struct fs_disk_quota dst, struct if_dqblk src)
	158	{
	159	dst->d_blk_hardlimit = src->dqb_bhardlimit;
	160	dst->d_blk_softlimit = src->dqb_bsoftlimit;
	161	dst->d_bcount = src->dqb_curspace;
	162	dst->d_ino_hardlimit = src->dqb_ihardlimit;
	163	dst->d_ino_softlimit = src->dqb_isoftlimit;
	164	dst->d_icount = src->dqb_curinodes;
	165	dst->d_btimer = src->dqb_btime;
	166	dst->d_itimer = src->dqb_itime;
	167
	168	dst->d_fieldmask = 0;
	169	if (src->dqb_valid & QIF_BLIMITS)
	170	dst->d_fieldmask \|= FS_DQ_BSOFT \| FS_DQ_BHARD;
	171	if (src->dqb_valid & QIF_SPACE)
	172	dst->d_fieldmask \|= FS_DQ_BCOUNT;
	173	if (src->dqb_valid & QIF_ILIMITS)
	174	dst->d_fieldmask \|= FS_DQ_ISOFT \| FS_DQ_IHARD;
	175	if (src->dqb_valid & QIF_INODES)
	176	dst->d_fieldmask \|= FS_DQ_ICOUNT;
	177	if (src->dqb_valid & QIF_BTIME)
	178	dst->d_fieldmask \|= FS_DQ_BTIMER;
	179	if (src->dqb_valid & QIF_ITIME)
	180	dst->d_fieldmask \|= FS_DQ_ITIMER;
	181	}
	182
c411e5f6 CH	183	static int quota_setquota(struct super_block *sb, int type, qid_t id,
	184	void __user *addr)
	185	{
c472b432	186	struct fs_disk_quota fdq;
c411e5f6	187	struct if_dqblk idq;
74a8a103	188	struct kqid qid;
c411e5f6 CH	189
	190	if (copy_from_user(&idq, addr, sizeof(idq)))
	191	return -EFAULT;
f450d4fe CH	192	if (!sb->s_qcop->set_dqblk)
f450d4fe CH	193	return -ENOSYS;
74a8a103 EB	194	qid = make_kqid(current_user_ns(), type, id);
	195	if (!qid_valid(qid))
	196	return -EINVAL;
c472b432	197	copy_from_if_dqblk(&fdq, &idq);
74a8a103	198	return sb->s_qcop->set_dqblk(sb, qid, &fdq);
c411e5f6 CH	199	}
	200
	201	static int quota_setxstate(struct super_block sb, int cmd, void __user addr)
	202	{
	203	__u32 flags;
	204
	205	if (copy_from_user(&flags, addr, sizeof(flags)))
	206	return -EFAULT;
f450d4fe CH	207	if (!sb->s_qcop->set_xstate)
f450d4fe CH	208	return -ENOSYS;
c411e5f6 CH	209	return sb->s_qcop->set_xstate(sb, flags, cmd);
	210	}
	211
	212	static int quota_getxstate(struct super_block sb, void __user addr)
	213	{
	214	struct fs_quota_stat fqs;
	215	int ret;
f450d4fe CH	216
	217	if (!sb->s_qcop->get_xstate)
	218	return -ENOSYS;
c411e5f6 CH	219	ret = sb->s_qcop->get_xstate(sb, &fqs);
	220	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
	221	return -EFAULT;
	222	return ret;
	223	}
1da177e4	224
af30cb44 CS	225	static int quota_getxstatev(struct super_block sb, void __user addr)
	226	{
	227	struct fs_quota_statv fqs;
	228	int ret;
	229
	230	if (!sb->s_qcop->get_xstatev)
	231	return -ENOSYS;
	232
	233	memset(&fqs, 0, sizeof(fqs));
	234	if (copy_from_user(&fqs, addr, 1)) /* Just read qs_version */
	235	return -EFAULT;
	236
	237	/* If this kernel doesn't support user specified version, fail */
	238	switch (fqs.qs_version) {
	239	case FS_QSTATV_VERSION1:
	240	break;
	241	default:
	242	return -EINVAL;
	243	}
	244	ret = sb->s_qcop->get_xstatev(sb, &fqs);
	245	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
	246	return -EFAULT;
	247	return ret;
	248	}
	249
c411e5f6 CH	250	static int quota_setxquota(struct super_block *sb, int type, qid_t id,
	251	void __user *addr)
	252	{
	253	struct fs_disk_quota fdq;
74a8a103	254	struct kqid qid;
c411e5f6 CH	255
	256	if (copy_from_user(&fdq, addr, sizeof(fdq)))
	257	return -EFAULT;
c472b432	258	if (!sb->s_qcop->set_dqblk)
f450d4fe	259	return -ENOSYS;
74a8a103 EB	260	qid = make_kqid(current_user_ns(), type, id);
	261	if (!qid_valid(qid))
	262	return -EINVAL;
	263	return sb->s_qcop->set_dqblk(sb, qid, &fdq);
c411e5f6 CH	264	}
	265
	266	static int quota_getxquota(struct super_block *sb, int type, qid_t id,
	267	void __user *addr)
	268	{
	269	struct fs_disk_quota fdq;
74a8a103	270	struct kqid qid;
c411e5f6 CH	271	int ret;
c411e5f6 CH	272
b9b2dd36	273	if (!sb->s_qcop->get_dqblk)
f450d4fe	274	return -ENOSYS;
74a8a103 EB	275	qid = make_kqid(current_user_ns(), type, id);
	276	if (!qid_valid(qid))
	277	return -EINVAL;
	278	ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
c411e5f6 CH	279	if (!ret && copy_to_user(addr, &fdq, sizeof(fdq)))
	280	return -EFAULT;
	281	return ret;
	282	}
	283
9da93f9b ES	284	static int quota_rmxquota(struct super_block sb, void __user addr)
	285	{
	286	__u32 flags;
	287
	288	if (copy_from_user(&flags, addr, sizeof(flags)))
	289	return -EFAULT;
	290	if (!sb->s_qcop->rm_xquota)
	291	return -ENOSYS;
	292	return sb->s_qcop->rm_xquota(sb, flags);
	293	}
	294
c411e5f6 CH	295	/* Copy parameters and call proper function */
c411e5f6 CH	296	static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
f00c9e44	297	void __user addr, struct path path)
c411e5f6	298	{
c988afb5 CH	299	int ret;
	300
	301	if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
	302	return -EINVAL;
2c5f648a JK	303	/*
	304	* Quota not supported on this fs? Check this before s_quota_types
	305	* since they needn't be set if quota is not supported at all.
	306	*/
c988afb5 CH	307	if (!sb->s_qcop)
c988afb5 CH	308	return -ENOSYS;
2c5f648a JK	309	if (!(sb->s_quota_types & (1 << type)))
2c5f648a JK	310	return -EINVAL;
c988afb5 CH	311
	312	ret = check_quotactl_permission(sb, type, cmd, id);
	313	if (ret < 0)
	314	return ret;
	315
c411e5f6 CH	316	switch (cmd) {
c411e5f6 CH	317	case Q_QUOTAON:
f00c9e44	318	return quota_quotaon(sb, type, cmd, id, path);
c411e5f6	319	case Q_QUOTAOFF:
f450d4fe CH	320	if (!sb->s_qcop->quota_off)
f450d4fe CH	321	return -ENOSYS;
307ae18a	322	return sb->s_qcop->quota_off(sb, type);
c411e5f6 CH	323	case Q_GETFMT:
	324	return quota_getfmt(sb, type, addr);
	325	case Q_GETINFO:
	326	return quota_getinfo(sb, type, addr);
	327	case Q_SETINFO:
	328	return quota_setinfo(sb, type, addr);
	329	case Q_GETQUOTA:
	330	return quota_getquota(sb, type, id, addr);
	331	case Q_SETQUOTA:
	332	return quota_setquota(sb, type, id, addr);
	333	case Q_SYNC:
6ae09575 CH	334	if (!sb->s_qcop->quota_sync)
6ae09575 CH	335	return -ENOSYS;
ceed1723	336	return sb->s_qcop->quota_sync(sb, type);
c411e5f6 CH	337	case Q_XQUOTAON:
c411e5f6 CH	338	case Q_XQUOTAOFF:
c411e5f6	339	return quota_setxstate(sb, cmd, addr);
9da93f9b ES	340	case Q_XQUOTARM:
9da93f9b ES	341	return quota_rmxquota(sb, addr);
c411e5f6 CH	342	case Q_XGETQSTAT:
c411e5f6 CH	343	return quota_getxstate(sb, addr);
af30cb44 CS	344	case Q_XGETQSTATV:
af30cb44 CS	345	return quota_getxstatev(sb, addr);
c411e5f6 CH	346	case Q_XSETQLIM:
	347	return quota_setxquota(sb, type, id, addr);
	348	case Q_XGETQUOTA:
	349	return quota_getxquota(sb, type, id, addr);
	350	case Q_XQUOTASYNC:
8c4e4acd CH	351	if (sb->s_flags & MS_RDONLY)
8c4e4acd CH	352	return -EROFS;
4b217ed9	353	/* XFS quotas are fully coherent now, making this call a noop */
8c4e4acd	354	return 0;
c411e5f6	355	default:
f450d4fe	356	return -EINVAL;
1da177e4	357	}
1da177e4 LT	358	}
1da177e4 LT	359
56df1278 LJ	360	#ifdef CONFIG_BLOCK
56df1278 LJ	361
dcdbed85 JK	362	/* Return 1 if 'cmd' will block on frozen filesystem */
	363	static int quotactl_cmd_write(int cmd)
	364	{
	365	switch (cmd) {
	366	case Q_GETFMT:
	367	case Q_GETINFO:
	368	case Q_SYNC:
	369	case Q_XGETQSTAT:
af30cb44	370	case Q_XGETQSTATV:
dcdbed85 JK	371	case Q_XGETQUOTA:
	372	case Q_XQUOTASYNC:
	373	return 0;
	374	}
	375	return 1;
	376	}
	377
56df1278 LJ	378	#endif /* CONFIG_BLOCK */
56df1278 LJ	379
9361401e DH	380	/*
	381	* look up a superblock on which quota ops will be performed
	382	* - use the name of a block device to find the superblock thereon
	383	*/
dcdbed85	384	static struct super_block quotactl_block(const char __user special, int cmd)
9361401e DH	385	{
	386	#ifdef CONFIG_BLOCK
	387	struct block_device *bdev;
	388	struct super_block *sb;
91a27b2a	389	struct filename *tmp = getname(special);
9361401e DH	390
9361401e DH	391	if (IS_ERR(tmp))
e231c2ee	392	return ERR_CAST(tmp);
91a27b2a	393	bdev = lookup_bdev(tmp->name);
9361401e DH	394	putname(tmp);
9361401e DH	395	if (IS_ERR(bdev))
e231c2ee	396	return ERR_CAST(bdev);
dcdbed85 JK	397	if (quotactl_cmd_write(cmd))
	398	sb = get_super_thawed(bdev);
	399	else
	400	sb = get_super(bdev);
9361401e DH	401	bdput(bdev);
	402	if (!sb)
	403	return ERR_PTR(-ENODEV);
	404
	405	return sb;
	406	#else
	407	return ERR_PTR(-ENODEV);
	408	#endif
	409	}
	410
1da177e4 LT	411	/*
	412	* This is the system call interface. This communicates with
	413	* the user-level programs. Currently this only supports diskquota
	414	* calls. Maybe we need to add the process quotas etc. in the future,
	415	* but we probably should use rlimits for that.
	416	*/
3cdad428 HC	417	SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
3cdad428 HC	418	qid_t, id, void __user *, addr)
1da177e4 LT	419	{
	420	uint cmds, type;
	421	struct super_block *sb = NULL;
f00c9e44	422	struct path path, *pathp = NULL;
1da177e4 LT	423	int ret;
	424
	425	cmds = cmd >> SUBCMDSHIFT;
	426	type = cmd & SUBCMDMASK;
	427
6ae09575 CH	428	/*
	429	* As a special case Q_SYNC can be called without a specific device.
	430	* It will iterate all superblocks that have quota enabled and call
	431	* the sync action on each of them.
	432	*/
	433	if (!special) {
	434	if (cmds == Q_SYNC)
	435	return quota_sync_all(type);
	436	return -ENODEV;
1da177e4 LT	437	}
1da177e4 LT	438
f00c9e44 JK	439	/*
	440	* Path for quotaon has to be resolved before grabbing superblock
	441	* because that gets s_umount sem which is also possibly needed by path
	442	* resolution (think about autofs) and thus deadlocks could arise.
	443	*/
	444	if (cmds == Q_QUOTAON) {
815d405c	445	ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW\|LOOKUP_AUTOMOUNT, &path);
f00c9e44 JK	446	if (ret)
	447	pathp = ERR_PTR(ret);
	448	else
	449	pathp = &path;
	450	}
	451
dcdbed85	452	sb = quotactl_block(special, cmds);
0aaa6188 JK	453	if (IS_ERR(sb)) {
	454	ret = PTR_ERR(sb);
	455	goto out;
	456	}
6ae09575	457
f00c9e44	458	ret = do_quotactl(sb, type, cmds, id, addr, pathp);
1da177e4	459
6ae09575	460	drop_super(sb);
0aaa6188	461	out:
f00c9e44 JK	462	if (pathp && !IS_ERR(pathp))
f00c9e44 JK	463	path_put(pathp);
1da177e4 LT	464	return ret;
1da177e4 LT	465	}